Charged particle beam device and method for inspecting and/or imaging a sample

Abstract

A charged particle beam device for imaging and/or inspecting a sample is described. The charged particle beam device includes a beam emitter for emitting a primary charged particle beam, the charged particle beam device adapted for guiding the primary charged particle beam along an optical axis to the sample for releasing signal particles; a retarding field device for retarding the primary charged particle beam before impinging on the sample, the retarding field device including an objective lens and a proxy electrode, wherein the proxy electrode includes an opening allowing a passage of the primary charged particle beam and of the signal particles; a first detector for off-axial backscattered particles between the proxy electrode and the objective lens; and a pre-amplifier for amplifying a signal of the first detector, wherein the pre-amplifier is at least one of (i) integrated with the first detector, (ii) arranged adjacent to the first detector inside a vacuum housing of the charged particle beam device, and (iii) fixedly mounted in a vacuum chamber of the charged particle beam device. Further, a method for imaging and/or inspecting a sample with a charged particle beam device is described.

The invention claimed is: 
     
       1. A charged particle beam device for imaging and/or inspecting a sample, comprising: a beam emitter for emitting a primary charged particle beam, the charged particle beam device adapted for guiding the primary charged particle beam along an optical axis to the sample for releasing signal particles; a retarding field device for retarding the primary charged particle beam before impinging on the sample, the retarding field device comprising an objective lens and a proxy electrode, wherein the proxy electrode comprises an opening allowing a passage of the primary charged particle beam and of the signal particles; a first detector for off-axial backscattered particles, the first detector arranged between the proxy electrode and the objective lens and configured to act as a further electrode for influencing at least one of the primary charged particle beam or the signal particles; and a pre-amplifier for amplifying a signal of the first detector, wherein the pre-amplifier is at least one of: (i) integrated with the first detector, (ii) arranged adjacent to the first detector inside a vacuum housing of the charged particle beam device, and (iii) fixedly mounted in a vacuum housing of the charged particle beam device. 
     
     
       2. The charged particle beam device according to  claim 1 , wherein the first detector is an in-lens detector with a hole allowing a passage of the primary charged particle beam and with a detection surface at least partially surrounding the hole. 
     
     
       3. The charged particle beam device according to  claim 1 , wherein the first detector comprises a support arranged between the objective lens and the proxy electrode or mounted at the objective lens, and the pre-amplifier is mounted on the support. 
     
     
       4. The charged particle beam device according to  claim 1 , wherein the first detector comprises a semiconductor detector with a detection surface, and the pre-amplifier is arranged inside the vacuum housing of the charged particle beam device at a distance of 3 cm or less from the detection surface. 
     
     
       5. The charged particle beam device according to  claim 1 , further comprising an amplifier for amplifying the pre-amplified signal provided by the pre-amplifier, the amplifier arranged outside the vacuum housing of the charged particle beam device. 
     
     
       6. The charged particle beam device according to  claim 1 , wherein the first detector includes a plurality of detector segments and the pre-amplifier is a multi-channel pre-amplifier. 
     
     
       7. The charged particle beam device according to  claim 1 , wherein the first detector comprises a conductive surface configured to be set on a predetermined potential. 
     
     
       8. The charged particle beam device according to  claim 1 , wherein the further electrode provided by the first detector is configured to be set on a ground potential. 
     
     
       9. The charged particle beam device according to  claim 1 , further comprising a second detector for secondary charged particles released from the sample, the second detector provided downstream of the objective lens in a travelling direction of the secondary charged particles. 
     
     
       10. A scanning electron microscope including the charged particle beam device according to  claim 1 , wherein the beam emitter is an electron source configured to emit a primary electron beam, the scanning electron microscope further comprising:
 a sample stage for supporting the sample; 
 a scan deflector for scanning the primary electron over a surface of the sample in a predetermined scanning pattern. 
 
     
     
       11. A charged particle beam device for imaging and/or inspecting a sample, comprising: a beam emitter for emitting a primary charged particle beam, the charged particle beam device adapted for guiding the primary charged particle beam along an optical axis to the sample for releasing signal particles; a retarding field device for retarding the primary charged particle beam before impinging on the sample, the retarding field device comprising an objective lens and a proxy electrode, wherein the proxy electrode comprises an opening allowing a passage of the primary charged particle beam and of the signal particles; a first detector for off-axial backscattered particles, the first detector arranged between the proxy electrode and the objective lens, wherein the first detector has an annular detection surface sized at least for detecting charged particles backscattered from the sample at angles between 15 degrees and 30 degrees relative to the optical axis; and a pre-amplifier for amplifying a signal of the first detector, wherein the pre-amplifier is at least one of: (i) integrated with the first detector, (ii) arranged adjacent to the first detector inside a vacuum housing of the charged particle beam device, and (iii) fixedly mounted in a vacuum housing of the charged particle beam device. 
     
     
       12. The charged particle beam device according to  claim 11 , wherein the annular detection surface is segmented and includes at least four detection segments. 
     
     
       13. A charged particle beam device for imaging and/or inspecting a sample, comprising: a beam emitter for emitting a primary charged particle beam, the charged particle beam device adapted for guiding the primary charged particle beam along an optical axis to the sample for releasing signal particles; a retarding field device for retarding the primary charged particle beam before impinging on the sample, the retarding field device comprising an objective lens and a proxy electrode, wherein the proxy electrode comprises an opening allowing a passage of the primary charged particle beam and of the signal particles; wherein the one opening is sized to allow a passage of the primary charged particle beam and of the signal particles, wherein the one opening is sized to allow a passage of charged particles backscattered from the sample at angles from zero degrees to twenty degrees or above relative to the optical axis; a first detector for off-axial backscattered particles, the first detector arranged between the proxy electrode and the objective lens; and a pre-amplifier for amplifying a signal of the first detector, wherein the pre-amplifier is at least one of: (i) integrated with the first detector, (ii) arranged adjacent to the first detector inside a vacuum housing of the charged particle beam device, and (iii) fixedly mounted in a vacuum housing of the charged particle beam device. 
     
     
       14. The charged particle beam device according to  claim 13 , wherein the one opening is sized to allow a passage of charged particles backscattered from the sample at angles from 0° to 45° or above relative to the optical axis. 
     
     
       15. The charged particle beam device according to  claim 13 , wherein the one opening is a round or circular opening that is centrally intersected by the optical axis and has an opening diameter of 2 mm or more and 6 mm or less. 
     
     
       16. A method for imaging and/or inspecting a sample with a charged particle beam device, comprising: emitting a primary charged particle beam; guiding the primary charged particle beam along an optical axis to the sample for generating signal particles; focusing and retarding the primary charged particle beam with a retarding field device comprising an objective lens and a proxy electrode arranged between the objective lens and the sample; detecting off-axial backscattered particles with a first detector arranged between the proxy electrode and the objective lens, wherein the first detector acts as a further electrode that is set essentially on a potential of a column of the charged particle beam device; and pre-amplifying a signal of the first detector with a pre-amplifier mounted adjacent to the first detector in a vacuum environment. 
     
     
       17. The method of  claim 16 , wherein the first detector includes a support arranged between the objective lens and the sample or mounted at the objective lens, and the pre-amplifier is mounted on the support. 
     
     
       18. The method of  claim 16 , wherein the proxy electrode comprises one opening allowing a passage of the primary charged particle beam and of the signal particles, wherein the one opening is sized to allow a passage of charged particles backscattered from the sample at angles from 0° to 20° or above relative to the optical axis. 
     
     
       19. The method according to  claim 16 , wherein a potential difference between the proxy electrode and the further electrode is between 3 keV and 35 keV.